Vitamin D deficiency before age 45 was associated with a threefold increased
risk for hypertension in midlife.

Researchers analyzed data from a Michigan Bone Health and Metabolism Study
that followed 559 women in their late 20s, 30s, and early 40s for 15 years.
Vitamin D levels were measured soon after the women entered the study and blood
pressure readings were taken each year.

By the end of the trial, when the average age of the women was 53, about one
in four had developed high blood pressure.

Vitamin D deficiency earlier in life appeared to be a predictor of
hypertension more than a decade later, lead researcher Flojaune C. Griffin, MPH, tells WebMD.

The research was presented in Chicago at the American Heart Association's
63rd High Blood Pressure Research Conference.

"This is preliminary data so we can't say with certainty that low vitamin D
levels are directly linked to high blood pressure," says Griffin, who is a
doctoral candidate in epidemiology at the University of Michigan. "But this may
be another example of how what you do early in life impacts your health years
later."

With the exception of bone diseases such as rickets and osteoporosis, which
are clearly linked to vitamin D deficiency, none of these associations has been
proven, however.

Exposure to sunlight is the easiest way to get enough of the vitamin,
because the body uses ultraviolet rays from the sun to make vitamin D.

Many foods -- including milk, yogurt, breads, and cereals -- are fortified
with vitamin D, but experts say that it would be very difficult to get adequate
levels of the vitamin from food sources alone.

And there is no consensus regarding the optimal supplement dosage of vitamin
D. Most multivitamins contain 400 international units (IU) of the vitamin, but
Griffin says much of the current research suggests that the optimal dosage may
be closer to 10 times this amount.

"It may be time to consider the possibility that we need a more nuanced
public health message about sun exposure so that we are not putting people at
risk for skin cancer, but are also alerting them to the fact that a few minutes
of exposure before they put on sunscreen may be a good thing," she says.

More Study Needed, Experts Say

Study co-author and University of Michigan professor of epidemiology Mary
Fran Sowers, PhD, agrees that the public health message advocating head-to-toe,
24/7 protection from the sun may need to change.

"We have recognized for a long time that it takes very limited sun exposure
to get adequate vitamin D," she says.

Hypertension expert Rhian M. Touyz, MD, PhD, of the University of Ottawa,
says the idea that vitamin D levels decades earlier can influence blood
pressure in middle age is intriguing but unproven.

"This definitely needs more study," she tells WebMD.

Cardiologist Nieca Goldberg, MD, who directs the Women's Heart Program at
New York University, agrees.

"This research certainly raises some interesting questions," she tells
WebMD. "Vitamin D is important for the absorption of calcium and its role in
bone health is proven. If we find out that it also helps prevent high blood
pressure, that's a real plus. But we aren't there yet."